Various types and amounts of chemical species are added to a papermaking process. In particular, chemicals are added into a process line of the papermaking process. The optimal location of injection of these chemical species is both a quality and a cost issue in that the optimal injection of the chemical species into a process line results in the following: a) better runnability of the paper machine; b) the quantity of the end product is more predictable and uniform; c) less web breaks and down-time of the paper machine; d) a reduction in the quantity of the chemical that needs to feed into a papermaking machine; e) smaller consumption of fresh water; and f less energy is needed to heat fresh water.
Titanium dioxide is a pigment used in the papermaking process to improve opacity of the sheet. Titanium dioxide helps make the sheet whiter while making the sheet less light-penetrable. In a typical papermaking process, titanium dioxide is added to a furnish as a dispersion in an aqueous liquid to the wet end of the papermaking process prior to the fan pump. Such addition typically results in uneven distribution of titanium dioxide across the sheet. The typical papermaking process adds excess titanium dioxide to the furnish in order to meet quality standards related to opacity, thereby increasing the cost of production.